**5.2 Dimensions marking**

The marking of dimensions (Fig. 5) for biodigester unit should be performed prior to start of excavation work. The marking is considered as preparation for excavation and construction works. An operational area of 3 m width around the digester should be considered, where the workers will use this area to achieve the construction works around the tank base in order to prepare the structure of the concrete base, i.e. the bottom of the digester.

Fig. 5. Marking of dimensions for a biodigester
